Electronic sights have recently been developed to aid a shooter in hitting a target when firing a gun, bow, crossbow, or the like. In an electronic sight, a dot of light is reflected from a front lens for viewing by a shooter. The shooter views the target through the sight and places the dot of light over the target on the intended point of impact. The projectile will impact at the point covered by the dot of light, provided the scope is properly aligned with the gun.
The basic principles of operation of an electronic sight are well-known in the art. A light source projects a narrow beam of light onto a specially coated lens. Light is reflected by a reflecting lens to the eye of the shooter. The light is seen by the shooter as a small, colored dot appearing on the lens. The lens also permits the shooter to simultaneously see objects through the lens. The dot of light on the lens becomes the aiming point. The light dot overlays the point of impact of the projectile expelled from the firearm at the particular range for which the gun sight is adjusted. The intensity of the aiming dot is adjustable by a voltage control that allows the shooter to increase or decrease the brightness of the light.
The electronic sight differs from conventional telescopic sights in that there is no magnification of the field of view as viewed through the sight. The object aligned with the intended target is a dot of light, not an etched cross-hair pattern. Electronic sights are described in a publication by Aimpoint describing the Aimpoint 2000 Series electronic sight and Pat. Nos. 3,942,901; 3,963,356 and 4,402,605, each of which is incorporated herein by reference.
Electronic sights presently in use are extremely expensive and difficult to make. The sight tube is made from precision castings. These are very expensive and restrict changes in the sight. This results in very high production costs and expensive tooling requirements. The sight tubes presently in use are circular, the lenses therein having the same vertical and horizontal dimensions. The lenses are held in place by threaded lens retainers that are costly to manufacture and costly to assemble.
The position of the light source (usually a light-emitting diode (LED)), with respect to the front reflective lens is critical. If the light source is not perfectly positioned to very tight tolerances, the lens will not properly reflect the light and the sight will not function properly. In present electronic sights, the mounting of the light source is manually performed on each sight to ensure that it is accurate. The present method of positioning the light source is to first drill an oversized hole. The light source is placed in this hole and held in position by the hand of the person building the scope. The person moves the light source by hand until it is properly aligned with the front lens. The light source is then glued into place and held by hand while the glue dries, to ensure that the light source does not move. This is not a reliable method of ensuring that the light source is properly aligned, and errors often occur in the alignment, resulting in a lower quality product than desired. Under rough handling or harsh field conditions, the glue may be jarred loose, ruining the sight. Further, this is an expensive and time-consuming method of placing the LED in position.